Highways Agency - Safe roads, Reliable journeys, Informed travellers

A419 Commonhead Junction

Non-Technical Summary of Environmental Statement, January 2005

Introduction

The Highways Agency has published details of a scheme to improve the A419 Commonhead Junction to the south east of Swindon with a new overpass. The A419/A417 trunk road is a key route for traffic travelling between the M4 (Swindon) and M5 (Gloucester).

The scheme is a development of the proposals which were the subject of Public Consultation in January and February 2003.

This Non-Technical Summary (NTS) leaflet describes the scheme and summarises the Environmental Statement (ES) which has been published in accordance with EC Directives as applied by section 105A of the Highways Act. The ES accompanies the draft Orders which have been published for this scheme.

Why the Scheme is Needed

The A419 trunk road is a strategic route linking the M4 and M5 motorways and links Swindon to the trunk and motorway network. Most of the route is already improved but Comonhead Junction is one of the remaining bottlenecks. Although the junction is traffic signal controlled it still suffers congestion. Queues of traffic can be over 1km in length to the north or the south of the junction depending on the time of day with delays of over 20 minutes. The junction has had more than 75 injury accidents over a 5 year period.

A new overpass at the junction would improve safety and resolve the current causes of congestion.

The Published Scheme

The new A419 Commonhead Junction would be a two level (grade separated) junction. The dual carriageway A419 would be carried on an embankment over the existing roundabout to allow free traffic flow on the trunk road. The A419 at Commonhead was originally constructed to allow a future overpass improvement and the existing A419 approaches to the new junction would be used as slip roads. All the new road works would be constructed within the highway boundary. Two bridges would be constructed to carry the A419 over the junction. The overpass would be built in the existing central reserves and would reach a maximum height of about 7m. Noise fencing and screen planting would be provided on the overpass and on the bund to the southand east of Liden. Improvements for pedestrians and cyclists would be provided to allow easier and safer crossing of the trunk road. The one-way access to Day House Lane would be closed.

Alternatives Considered

• Through-about (same level signal controlled junction)
• Underpass

A through-about would not provide sufficient traffic capacity for a long term solution.

An underpass would:

• require extensive retaining structures and permanent pumping of groundwater and rain water, which
• would have an adverse impact on groundwater and the local hydrology;
• increase the risk of flooding on the trunk road;
• require more complex construction due to working below the water table;
• produce large quantities of surplus excavated material.